Kidney-targeted gene transfer has the potential to revolutionize the treatment of renal diseases. Transplanted kidneys also provide an ideal setting for ex vivo gene transfer. Several in vivo gene transfer methods have been attempted to target certain renal structures, for example, the HVJ-liposome method and renal perfusion of adenovirus for glomerular cells, intravenous injection of oligonucleotides (ODNs) for proximal tubule, intra-arterial injection of adenovirus followed by cold incubation with a vasodilator for interstitial vasculature of the outer medulla and adenoviral injection into the renal pelvis for the inner medullary collecting duct. As an ex vivo gene transfer method targeting the glomerulus, the transfusion of genetically-modified mesangial cells has been attempted. Implantation of genetically-modified tubular epithelial cells into the subcapsular region has been employed for ex vivo transfection to the interstitium.
However, although gene therapy theoretically has the distinct potential to treat renal disease at the most fundamental level, its application has been limited by the availability of an adequate system for long term gene delivery to the kidney. There still exists a need for improved gene transfer techniques, especially gene transfer vectors that are capable of mediating effective gene transfer into renal tissues with low toxicity.